Knee pad



FIG. 1 is a front side perspective view of my design for a knee pad:

FIG. 2 is a bottom view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a front side view thereof; and,

FIG. 7 is a backside view thereof.

The broken lines shown in the drawings show unclaimed subject matter only and form no part of the claimed design. 

CLAIM The ornamental design for a knee pad, as shown and described. 